I thought it going to be like that James Bond movie, "From Russia with Love", where the assailant had a poison-tipped retracting spike in her shoe. I'm glad the woman survived. It must be pretty potent stuff. I guess while no one was around he slipped the stuff into her shoe, but she never felt anything wet in them when she put them back on?

WOW, scary story. People can be creative in quite a number of ways to kill someone. This is particularly heinous for there is no defense or even a way one could guard against such a unconventional attack. People from outside Japan could argue that you just don't let your private belongings out of your sight but in Japan you leave your shoes everywhere: hospitals, clinics, offices, houses, restaurants. (by the way not all places will require you to take your shoes off but a lot of them will)

Regardless of the "back storey" or "there's more to this story" nobody deserves to loose their toes and go through the agony of the surgery and recovery and rehabilitation both mentally and physically. People who perpetrate such hideous crimes against fellow human beings have no place in human society. They don't play by the rules so why should they get the benefit of them. Life in prison if convicted and removal of five toes so he can experience what she will experience for the rest of her life. Our civilised penalty system does not appear to deter uncivilised people. Bring back the "eye for an eye" penalty system and those that are intent on being uncivilised might think again or suffer the consequences of their actions. People who don't do this sort of thing would have nothing to worry about.

He didn't have to do too much homework if he got it from work, he must have know the side effects from on the job hazardous training.
His work place may need to be scrutinized a bit as well for no controlling the substance there.

It's good to know these kind of people are out there and that substances like this are this easily obtained by seemingly any old fool. Thankfully, kids are prohibited from using parks for ball games so we are safe.

HydroFluoric acid (HF) is used in various levels of concentration. Lower concentrations are dangerous and may not dissolve rocks. Higher levels are fatal in hours. This seems to have been a diluted level of HF.
This guy should be charged with attempted murder.

The man should be punished for both the crime and the failed attempt. It seems that no one can complete a single freakin' task anymore without screwing it up... Even criminals don't have any sense of pride or follow-through...